The present invention relates to the manufacture of gelled products such as jelly gum confectionaries and pharmaceutical products by extrusion, more particularly to extruded confectionaries and pharmaceutical products which include unique high amylose starches.
It has long been known that gum confections can be made with starch and, for many years, jelly bean centers and imitation fruit pieces, sometimes referred to as sugared jellies, have been made with ingredients including starch. These confectionaries have a firm gel structure. They are typically manufactured by a starch mold casting process, referred to in the trade as the Mogul system.
In this casting system, the ingredients, including a thin-boiling starch or a combination of a high amylose starch and a thin-boiling starch, are cooked at a moisture above the final moisture of the confectionary, and deposited as a thin, hot liquid into a mold generally formed of dry starch. The starch in the mold forms the confectionary pieces and serves to reduce the moisture content of the confectionary to the level of the end product. Typically, the cooked moisture level is about 15-30% in commercial continuous pressure cooking systems; the final moisture content is about 12-21%. This starch mold casting process has many disadvantages, particularly, the fact that the deposited candy pieces and molding starch must be dried for about 24-72 hours to reach the final product moisture content and a gel strength sufficient for handling and packaging.
An in-line extrusion process providing cooking and/or forming at the desired finished moisture content would be desirable. Most of the jelly gum confectionaries comprising jelly bean centers, imitation fruit pieces, and other snacks are presently made by the starch mold casting process. In order to get the desired gel structure, the starch has to be cooked at temperatures above the boiling point of the ingredients, i.e., above about 138.C. (280.F), and with moisture present in excess of that in the end product to achieve full gelatinization and a transparent to translucent gel. It is possible to cook at lower temperatures or with moisture starved conditions, but the starch does not fully dissolve and the ungelatinized starch essentially functions as a filler, with the consequence that the confectionary does not have the desired body, texture, and/or shelf life (i.e., the confectionary sweats which is due to inadequate gel structure).
Thus, it has been recognized that high temperature heating, well above the boiling temperature of the confectionary mixture, is required. In high temperature extrusion, one encounters problems with caramelization, air entrapment, and boiling and flash-off at the discharge orifice. The resultant textures range from that of hard candy to a tough licorice consistency. High temperature extrusion has not been successful in providing the classic resilient gel structure, clarity, and flavor attributes of the cast jelly gum confectionaries. Atmospheric cooking coupled with former extrusion (without heat) has not been successful in obtaining high quality gelled products due to poor set obtained from the starch when the candy is cooked under atmospheric conditions. Superatmospheric (i.e., steam injection) cooking, also referred to as jet-cooking, coupled with former extrusion (without heat) is also not commercially feasible due to the inability of the jet-cooker to handle very high viscosity finished solids confectionary formulations. High viscosity along with quick set are critical for the rope formation and handleability required for successful extrusion.
Various processes have been proposed for the manufacture of jelly gum confectionaries by extrusion.
U.S. Pat. Nos. 3,265,508 and 3,265,510 (issued Aug. 9, 1966 to O. B. Wurzburg et al.) describe extrusion processes. In the '508 patent the starch utilized is a converted starch containing no more than 35% amylose and having a fluidity above 20, e.g., dextrins and British gums. In the '510 patent the starch utilized is a native starch or a modified starch having a fluidity of less than 20. These thin-boiling starches do not provide a confectionary having the desired firm structure and transparent to translucent gel.
U.S. Pat. No. 3,265,509 (issued Aug. 9, 1966 to O. B. Wurzburg et al.) is also directed to an extrusion process. The starch utilized contains at least 50% amylose. High amylose starches typically require temperatures of at least about 149.degree. C. (300.degree. F.) even in dilute dispersions (below 50% solids) to gelatinize the starches. At the lower temperatures and higher solids levels used during extrusion (typically 80-86% solids), high amylose starches are not adequately gelatinized and largely function as fillers. At higher temperatures (about 204.degree. C.-400.degree. F.) the starches cook out but these conditions, which include an initial heating to about 82.degree.-204.degree. C. (180.degree.-400.degree. F.) and a die temperature in the range of about 32.degree.-79.degree. C. (90.degree.-175.degree. F.) and pressures ranging from about 50 to 5000 psi, are harsh, are difficult to obtain in most conventional extruders, and can lead to problems. The problems encountered include carmelization and off flavor development. Since heat-sensitive flavors have to be added prior to and/or during extrusion, it is important to be able to use mild extrusion conditions. As will be shown hereafter, it would be desirable to obtain a fast setting gel with a starch at milder extrusion conditions.
U.S. Pat. No. 4,567,055 (issued Jan. 28, 1986 to C. O. Moore) describes an extrusion process for the manufacture of jelly gum confectionaries wherein the starch utilized is an ungelatinized corn starch having a cold-water-solubility of greater than 25% which hydrates to be functional as a colloid. The cold-water soluble granular corn starches described in U.S. Pat. No. 4,465,702 (issued August 14, 1984 to J. E. Eastman) are suitable provided they have the required cold-water-solubility. As will be shown hereafter, the rapidity of gel formation resulting from this starch is not sufficient for the successful continuous extrusion of jelly gum confectionaries. In addition, jelly gum confectionaries made with this cold-water soluble corn starch have poor clarity.
Presently, jelly gum confectionaries are commercially manufactured by the casting process, which is a very lengthy process due mainly to the long time required for the confectionary to reach the required gel strength necessary for packaging. There is, therefore, a need for a process for preparing extruded jelly gum confectionaries which utilize starches that form firm gels quickly once cooked so that continuous extrusion can be successful.
Australian Patent Application P 36 12 212.2 describes injection molded or extruded pharmaceutical products prepared using a solvent-free N-vinylpyrrolid-2-one (NVP) polymer or copolymer as the fusible binder. Conventional extenders, such as silica or silicates, stearic acid or its salts, methylcellulose, talc, sucrose, lactose, cereal or corn starch, potato flour, or polyvinyl alcohol, can be used which include high amylose starches which entrap non-heat sensitive pharmaceutical compounds.
Presently, no extruded pharmaceutical products utilize starches to form a gelled matrix, contributing structure and encapsulating the active ingredients.